First US Digital Computer

[xoxoxoBruce]

Aiken-IBM Automatic Sequence Controlled Calculator Mark I.
Here is a detailed article detailing how it was built.

Commander Aiken modestly ascribes the conception of this device to his own laziness. He is a tall, blond, 42-year-old electrician and scholar. To finish high school, he had to take correspondence courses while employed nights by an Indianapolis power company as a switchboard attendant. This accounts for the construction of the calculator in the form of a switchboard. To complete his thesis for a doctor’s degree at Harvard, he had to make calculations that took him nearly a year. This accounts for his decision to see whether such a machine could not be built.

For two years, he did not mention his breath-taking idea to anyone. He had to convince himself first that it was feasible. Then, in 20 minutes, he interested an International Business Machines Corporation engineer in the idea. Clair D. Lake, a pioneer inventor of mechanisms for I.B.M., was put in charge of work on the plans. Three other I.B.M. experts, Frank E. Hamilton, Benjamin M. Durfee, and James W. Bryce, also became coinventors. It took the company six years and cost more than $250,000 to build the machine. I.B.M. then presented it to Harvard.